Meet the 25-year-old mother who gave birth to baby from 24-year-old embryo.

When Tina Gibson got married seven years ago, the 26-year-old knew it was unlikely that she would have children naturally. Her husband, 33-year-old Benjamin Gibson, had cystic fibrosis, a condition that can make men infertile, the couple told CNN.

The US couple decided they would eventually adopt a child instead - and that they would foster several children in the meantime, until they were ready.

Then, last year, during a break between foster children, her father told them about something he had heard on the news - embryo adoption. Mrs Gibson couldn't get the idea out of her head. She submitted an application for the adoption in August 2016, and had three embryos from the same anonymous donor transferred into her uterus.

It was only when she was preparing for the transfer that a doctor and lab director explained the embryos Gibson had chosen could lead to a "world record".

On November 25, Mrs Gibson gave birth to a healthy baby girl, Emma Wren Gibson.

"People say, 'oh it's science,' but no I think it's a gift from the Lord. It's a gift from the Lord, for sure," Mrs Gibson told local TV station WBIR.

The National Embryo Donation Centre in Knoxville, Tennessee - the embryo adoption program that helped Mrs Gibson get pregnant - said Emma holds the record for the longest-frozen embryo to come to birth, citing research staff at the University of Tennessee Preston Medical Library.
The embryo was frozen on October 14, 1992, when Mrs Gibson was about 18 months old, and was thawed on March 13, 2017, by embryology lab director Carol Sommerfelt, making it 24 years old, National Embryo Donation Centre officials said.

Surprised by the age of the thawed embryos, Mrs Gibson said in March, "Do you realise I'm only 25? This embryo and I could have been best friends," according to CNN.

But some experts say it's unclear whether Emma's birth is, in fact, a record. Dr Zaher Merhi, director of IVF research and development at New Hope Fertility Center, told CNN that American companies are not required to report the age of the embryos they transfer to the government - just the outcome of the pregnancies.

"Nobody has these records," he said.

Some experts say the previous record was set in 2011, when a woman in New York gave birth to a healthy boy born from a frozen embryo created 20 years earlier.

Ms Sommerfelt, who transferred the embryos into Mrs Gibson's uterus, said she was amazed that embryos of such an old age could result in the successful birth of a baby.

"It is deeply moving and highly rewarding to see that embryos frozen 24.5 years ago using the old, early cryopreservation techniques of slow freezing ... can result in 100 percent survival of the embryos," Ms Sommerfelt said.

About 12 per cent of American women 15 to 55 - or 7.3 million - have used some sort of fertility service, according to the Centres for Disease Control and Prevention. The use of assisted reproductive technologies doubled in the past decade, and in 2015, the procedures resulted in the births of 73,000 babies - about 1.6 per cent of all US births.